bool isPalindrome(char * s){
    int j=0,i=0;
    for( i=0;s[i] !='\0';i++)
    {
        if ((s[i] >= 'a' && s[i] <= 'z') || (s[i] >= 'A' && s[i] <= 'Z') || (s[i]>='0'&&s[i]<='9'))
        {
            if (s[i] >= 'A' && s[i] <= 'Z')
            {
                s[i] = s[i] + 32;
            }
            s[j++] = s[i];
        }
 
    }
    s[j] = '\0';
    i=0;
 
    for(i=0;i<j/2;i++)
    {
        if(s[i] != s[j-1-i])
        {
            return false;
        }
    }
 
    return true;
}